1. Field of the Invention
The present invention relates generally to an improved aerodynamic control effector for aircraft and, more particularly, to a control effector which provides increased aerodynamic control power per unit area, and greater control power at high angles of attack than conventional control effectors. Tie invention can be used to generate pitching, rolling, and yawing moments aerodynamically by collective and/or differential deflection of the incorporated moveable aerodynamic surfaces.
2. Description of the Prior Art
It is a continuing challenge for aircraft designers to improve the aerodynamic control and maneuvering capability of aircraft. Improving control and maneuvering is especially important for supersonic fighter aircraft. This is because they have special requirements related to their ability to "track" or "aim" the fuselage in a particular desired direction. Associated with this is a further requirement to change "tracking" or "aiming" direction quickly which is commonly called maneuverability.
Maneuvering flight means flight at high angles of attack. In that flight regime aircraft experience a severe degradation of aerodynamic control, and the large empennages typically associated with fighter aircraft are the usual design solutions to cope with these deficiencies. All-moving horizontal or V tails of the type which are currently used on high-speed military aircraft tend to lose control power at high angles of attack, due to aerodynamic stall of the tail surface. At angles of attack in excess of 30 to 40 degrees, the ability of a conventional tail to generate nose-down moments to drive the angle of attack down degrades to nil.
Typical of the prior art in this regard is U.S. Pat. No. 5,366,180 to Wainfan and Mrdeza which discloses a pair of foreplanes mounted on the forward portion of the aircraft together with a pair of co-planar strakes extending between the trailing edge of an associated foreplane and the leading edge of an associated wing. The patented combination controls forebody vortex flow, while the present invention, as will be explained, generates control power by manipulating the flow leaving the aft portion of the aircraft. That is, the movable portion of the patented invention is the forward portion of the device, while the movable portion of the present invention is the aft portion thereof.
U.S. Pat. No. 5,082,207 to Tulinius is primarily concerned with using flexibility of the wing of the aircraft for control and discloses a system for controlling an aircraft by aeroelastic deflections of the wings which is effective beyond control surface reversal. The control surfaces 34, 36 in FIG. 1 of the patent are the only components of the patented construction which are in any way similar to the present invention. They differ in that they are entirely behind the fixed portion of the body, and have no overhanging or projecting portions as is the case for the present invention. Additionally, the control surfaces 34, 36 are entirely co-planar with the aft portion of the fuselage of the aircraft, while in some embodiments of the present invention, the outboard portion of the control effector is not so configured.
U.S. Pat. No. 4,901,947 to Raymer discloses a short/vertical takeoff and landing aircraft including an engine mounted in the airframe in a reversed position having an inlet facing toward the rear of the aircraft and the exhaust nozzle assembly having a pair of exhaust nozzles facing toward the front. The exhaust nozzles extend outward from the sides of the aircraft and are rotatable from a vertically downward position to provide upward thrust to a horizontally rearward direction to provide forward thrust. The configuration disclosed has no control effectors which resemble the present invention.
U.S. Pat. No. 4,723,214 to Frei discloses a control system for optimization of vehicle performance which includes a strake flap but lacks the protruding portion of the movable control effector which is a feature of the present invention. Additionally, each strake flap is entirely co-planar with the aft portion of the body of the aircraft, while in some embodiments of the present invention, the outboard portion of the control effector is not co-planar with the fixed portion of the body.
U.S. Pat. No. 4,381,091 to Peagram discloses a strake fixed to the fuselage immediately forward of a horizontal stabilizer, but is in no way attached nor hinged to the movable tail surface. In the present invention the movable control surface is attached to the fixed portion by a hinge, preventing a gap from forming between the fixed and movable portions when the control surface is deflected, as would be the case for the system disclosed in the patent.
U.S. Pat. No. 4,691,879 to Greene discloses an aircraft including multiple airfoils and engines. The tail surface 44, 46 is essentially a conventional swept horizontal tail, and is not integrated with the body in the manner of the present invention. Additionally, the leading edge of a movable portion 46 is co-linear with the leading edge of a fixed portion. In the present invention, the exposed edge of the fixed portion is oriented essentially fore and aft, and its front edge is contiguous with the trailing edge of the wing. Additionally, the fixed and movable portions of the tail of the patented constriction are completely co-planar, while in some embodiments of the present invention, the outboard portion of the control effector is not co-planar with the fixed portion of the horizontal surface.
It was with knowledge of the foregoing that the present invention has been conceived and is now reduced to practice.